Epiphyllum cooperi, Epiphyllum crenatum
and Disocactus macranthus.
<I flowered my Epiphyllum cooperi...and started doing a little research. Ted Anderson’s book, ‘The Cactus Family’, lists it under Epiphyllum crenatum var. kimnachi. This puzzles me, as my general understanding is, that if it is a variety, there are only a few differences. I shall, at this stage refer to E. crenatum var. kimnachi, as E. cooperi. Lets look at features of three plants - E. crenatum, E. cooperi, and Disocactus macranthus and compare them. This information is based on my experience and observation.
| E. crenatum | E. cooperi | D. macrathus | ||
|---|---|---|---|---|
| Stem | Erect up to 1 metre Flattened  Clearly knotched, Overall comparision long, and rounded at the end - blunt * see photos |
Erect up to 25 – 35 cm Flattened  Minimally to not knotched Overall shape spear head shaped, tapers toward the tip |
Arching 20 –30 cm Flattened  Clearly knotched Spear shaped tapers towards the tip |
|
| New Growth | Generally from the base, but not uncommon on the stem. |
Almost always from the base near ground rarely anywhere else. |
Various anywhere (usually in the top 2/3) |
|
| Flowers | Grow from the top half to 2/3 of the stem  Stems have leaf like scales only. |
almost always from the base near ground Stems commonly hairy at  base with small scales higher  up the flower stem. |
Usually in the top 2/3 of each stem Stems have minimal scales. See photo below |
|
| Flowering time |
mid Spring for 3 + days |
late Spring early Summer for 3+ days |
Autumn for 3+ days | |
| Perfume Flower |
Perfumed – evening 7 – 11pm* |
Perfumed – evening 9pm – 1am* |
Perfumed – day Through the day* |
|
| Flower Shape |
Generally tends to cup shape – loose petals Flowers 18 – 23 cm in diameter with overall cream colour  redening by high light levels on the outer petals. |
open trumpet shape tight overlapping petals Flower 25 – 30 cm in diameter with white /cream petals  that darken to pale yellow in the centre |
star wheel shape narrow petals Flowers 6cm in diameter with  yellow petals |
|
| Petal edge shape |  |
 |
||
| Fruit | round about golf ball or larger size 3 - 4 cm  Takes in Auckland four months to ripen (through summer) Has scales red when ripe |
same size, but has an angular surface  “takes longer” to ripen - 12 months. Hairs (no scales) green/yellow when ripe |
smaller round berry, less than 1.5 cm takes 4 - 5 months through winter Minimal scales red when ripe |
* The perfume of these flowers are all slightly different.
The time mentioned above are roughly when they are their strongest.
If E. cooperi is a variety of E. crenatum, then one would expect many similarities.
Similarities:
1) Erect stem
2) Three plus days flowering
3) Flowers are perfumed at night - note time differences
Differences:
(Significant to be clearly distinct)
1) Where flowers originate from
2) Stem shape
3) Present/absence of scales/hairs on flower stem base
4) Flower shape
5) Flower perfume different
6) Different flowering time
7) Fruit difference - scales vs hairs
8) Fruit flavour significantly different
9) Fruit ripening time significantly different
10) Fruit ripening colour green vs red colour So, E. cooperi is distinctly different from E. crenatum, and calling it E. crenatum var. kimnachi makes one ask questions. Such as - how many significant variations from a species can a plant have and still be considered a variety of a species? Maybe Disocactus macranthus could be considered a variety of E.crenatum as well!
Until the naming system for this whole group of epiphytic cacti is sorted out, E. cooperi (from long-time common usage) seems as appropriate as any other name. I don't feel it can be considered a variety of E. crenatum, because of the significant differences.